This means
(1) Sun = 6 years = 6,000 * 4 = 24,000
(2) Moon = 10 years = 10,000 * 4 = 40,000
(3) Mars = 7 years = 7,000 * 4 = 28,000
(4) Mercury = 17 years = 17,000 * 4 = 68,000
(5) Jupiter = 16 Years = 16,000 * 4 = 64,000
(6) Venus = 20 Years = 20,000 * 4 = 80,000
(7) Saturn = 19 Years = 19,000 * 4 = 76,000
(8) Rahu = 18 Years = 18,000 * 4 = 72,000
(9) Ketu = 7 Years = 7,000 * 4 = 28,000

Number and Procedure of Jaap, Havan, Tarpan, Maarjan, Brahman Bhojan
Havan = 1/10 of Jaap
Tarpan,= 1/10 of Havan
Marjan,= 1/10 of Tarpan
Brahman bhojan = 1/10 of Maarjan

For example:
Mantra Jaap = 100,000 (1,000 Mala / Rounds of Rosary)
Havan = 10 % of Mantra Jaap = 10 % of 1,00,000 = 10,000 (100 Maalaa)
Tarpan = 10 % of Havan = 10 % of 10,000 = 1,000 (10 Maalaa)
Maarjan = 10 % of Tarpan = 10 % of 1,000 = 100 (1 Maalaa)
Braahman Bhojan = 10 % of 100 = 10 Braahman

If one is not doing Havan, Tarpan, Maarjan, then after Mantra Jaap one should take Sankalp for Tarpan and do twice Jaap for Tarpan, and twice Jaap for Maarjan, so the numbers they become

Jap in lieu of Havan = 2 * 100 = 200 Mala
Jap in lieu of Tarpan = 2 * 10 = 20 Mala
Jap in lieu of Maarjan = 2 * 1 = 2 Mala
Jap in lieu of Brahman = 1 Maalaa (if less than 108, we do at least one 1 Maalaa)

Samidhaa (wood sticks) for various planets

(1) Sun = Aak Wood
(2) Moon = Palaash Wood
(3) Mars = Khair Wood
(4) Mercury = Apa-maarg Wood
(5) Jupiter = Peepal Wood
(6) Venus = Goolar Wood
(7) Saturn = Shami Wood
(8) Raahu = Druva
(9) Ketu = Kusha

Saamagree for each Aahuti adding Swaahaa
Til (white sesame seed) = x (you decide this depending on the number of Aahuti required)
Rice = x 2
Yava (barley) = x 4
Sugar = x 8
Gud (Jaggery) = x 8
Yogurt (Dahee or Curd) = x 8
Ghee (Clarified Butter) = x 16

Now specifically taking your example of Venus.
Venus Jaap = 80,000
Number of Aahutis required saying "Om Draam Dreem Draum Sah Shukraaya Namah Swaahaa" = 10 % of 80,00 = 8,000 (this means 80 rounds of rosary)

But to be practical, I never put that many Aahutis because it's very expensive, although it's ideal thing to do but it's expensive.
Like what I will do is, Make 1000 Aahuti = 10 Maalaa. (Maalaa = rosary of 108 beads round), So I am left with 70 Maalaa, so I will do 140 more rounds in lieu of ideal 70 more Maalaa Havan that was required.

But be careful, you will have to announce this in the Sankalp for Havan that you will give 1000 Aahuti and then do double Jaap for remaining Aahutis (offerings).
Or you can completely skip Hom and directly do 80*2 = 160 rounds of rosary by taking Sankalp.

But I usually prefer at least some Hom, because it mean what you are offering to fire, breaks up into subtle form and goes directly to the deity for whom you are doing the Hom.

And further about the Saamagree for Homam - Lets say you have to do homam for 1,000 Ahutis.
Lets say that takes 1600 grams of ahuti (=> x = 1600gm)

(very rough example, but I am using this number 1600 for sheer ease of calculation)

(1) Til (white sesame seed)= 1600 gm
(2) Rice = 800 gm
(3) Yava (barley) = 400 gm
(4) Sugar = 200 gm
(5) Gud (Jaggery) = 200 gm
(6) Yogurt (Dahee or Curd) = 200 gm
(7) Ghee (Clarified Butter) = 100gm

Total Weight of Mixture = 3500 gm = 3.5 kg

You have to offer the a mixture with this composition okay, "the mixture" for Aahuti.

Remember, take the Til amount as the mean.
And to be precise, if you want to be very scientific about it, then calculate total amount of Aahuti that you can put on a small teaspoon.
Multiply that by the number of Aahutis you want, then you will get the total weight of the mixture you need and then decide quantity of
specific ingredient accordingly.

Oh and one thing more, remember this composition of mixture is for Nava Graha Shaanti, for Hom of other purpose, Samidhaa (wood), ingredients of Aahuti and basically whole procedure may be different. So if this is your first Hom, then remember this composition applies to Nava Graha Shaanti only.