Ost vs S4 for Recomp / Fat Loss

[Kagenical]

Hello all,

I have both mk2866 (ost) and S4 on hand, and was wondering which would be best to preserve LBM and possibly recomp a bit during a strict 6 week cut.

I'll be doing a keto style IF diet with around a ~1000kcal under TDEE (eating around 1800kcal/day, TDEE assumed 2800Kcal), macros will be around 140g protein, 10g carbs, 120g fat. This allows for a fairly good 70/30 fatrotein calorie ratio.

I'll be lifting 3x per week, doing a basic bodyweight split focusing on one major lift per day, lowering reps but increasing sets and keeping weights the same, hoping to progress a bit.
3 other days of the week I'm doing light intervals (2m/2m) to increase my cardio capacity for summer sports with friends.
I walk around 5 miles a day which is why my TDEE is high for my weight/size.

Stats:
25 yo, 5'10", 175lbs, 15% bf.
405lb DL, 425lb Squat, 180lb bench (lol), 155lb standing military.
Have been training naturally for around 3 years, after dropping around 120lbs of fat.

Hoping to hit 10% BF by losing 10lbs or so during these 6 weeks.

Many people recommend S4 during a cut because it increases vascularity/shreddedness lowers water retention - which I don't really care about. I don't want to *look* leaner at the end of 6 weeks - I want to optimize fat loss. Every gram I can lose is well appreciated. I can worry about looking lean and dry when my BF is low enough by manipulating estrogen if I really want.

So my question... S4 at 50mg/day, or mk2866 at 12-25mg day. Both?
Anyone ever do a low dose of both? Say 12.5mg Ostarine, 25mg S4?

Any other supplements that synergize well with your SARM of choice?

Cheers!