Replying to Msnow vs turf

I'm building a drop in for my summer setup with some old pallets and msnow, but i'm not sure if it's gonna give me enough speed to clear a 12ft tube. i've seen other drop ins that are significantly taller and longer, but they're covered in turf instead of msnow, so i'm just wondering which slides better. hopefully, if turf isn't as fast, i won't have to change what i have now (its around 3.5ft tall i'm already pretty worried about making it too tall and unstable). do you guys have any input on how well each slides? i'm also adding some pics of what i have so far if you guys have any suggestions. thanks