mounting a swim step

[bigbad 4cyl x2]

i got some great tips on my last thread .i need help now for my swim step . i need to mount the brackets ,but they are drilled for 1/4 inch holes . that's kind of small with all the weight going on there . im also wondering if i should through bolt the brackets or use lag screws with 5200 . im starting to feel like i should through bolt the top 2 sets of bolts ,then just lag the bottom 2 set were they might be so low as to be into the foam ;

 

[rjwoodrome]

Re: mounting a swim step

Had a good look at mine from the underside. 1/4" bolts, washers, and a back plate, to help spread out the weight distribution.